Stabilized hydrogen peroxide and method of making same



Patented Nov. 10, 1953 STABILIZED HYDROGEN PEROXIDE AND METHOD OF MAKING SAME Edward S. Shanley, Grand Island, and Hans 0.

Kaufl-mann, Eggertsville, N. Y., assignors to Buflalo Electro-Chemi Wanda, N. Y.

cal Company, Inc., Tona- No Drawing. Application October 5, 1945,

Serial No. 620,626

Claims. 1

The present invention relates to an improvement in methods of stabilizing hydrogen peroxide solutiona'to an improved stabilized aqueous hydrogen peroxide and, in particular, to the employment of oolloidally dispersed metallic tin as the stabilizing material.

Hydrogen peroxide is an important article of commerce the use of which, in industry, is increasing year by year. Heretofore, hydrogen peroxide was shipped in small quantities in glass carboys. Presently, however, hydrogen peroxide is shipped in tank cars and stored in substantial quantities at distribution centers or at the locality of use. Due to this method of shipping and storage, there is a continual demand that the hydrogen peroxide be of somewhat higher stability than that furnished in the past; that is to say, that it resist the decomposing action of heat and light to a greater degree and that the product be capable of storage over long periods of time without deterioration in strength.

Aqueous solutions of hydrogen peroxide are available as articles of commerce and, in general, the standard 100 volume hydrogen peroxide, about 27.5% hydrogen peroxide by weight, is generally stabilized by adding stabilizing chemicals thereto, which chemicals may be present from about 500 to 1250 milligrams per liter, more Or less. Hydrogen peroxide is now employed in many processes where residues of this amount and character are undesirable.

It is an object of the present invention to stabilize hydrogen peroxide solutions by the employment of extremely small amounts of a stabilizing agent, an agent which does not interfere with the uses to which hydrogen peroxide is put and in amounts which do not interfere with, the sensitive reactions into which the peroxide enters.

It is a further object of the invention to stabilize acid or neutral hydrogen peroxide with very small amounts of colloidally dispersed metallic tin.

In accordance with the invention, a dispersion of metallic tin may be prepared, in accordance with the procedure of Bredig, by forming an electric arc between tin electrodes under distilled water and permitting arcing to continue for a time sufiicient to produce a tin sol. 'After standing several days, coarse particles of tin torn from the electrodes, by the disruptive action of the arc, were removed and the colloidal suspension analyzed gravimetrically and found to contain 460 milligrams of metallic tin per liter. In orderto determine the stabilizing efiect of this colloidal dispersion of tin, samples of redistilled 30% hy- 4 drogen peroxide, containing a very small amount of residue and no added stabilizing material, were treated with sufficient of the aqueous colloidal solution of tin so as to contain 2 milligrams per liter of tin in one sample, and 20 milligrams per liter of tin in another sample, 1. e., approximately 2 p. p. m. and 20 p. p. m. respectively. The samples of peroxide so treated were subjected to an accelerated decomposition or stability test by placing them in a water bath at C. for'24 hours and, at the end of that period, determin-' ing the amount of active oxygen lost by decom-. position. Measured samples of the untreated and of the treated peroxide were titrated in the regular way with N/ 10 permanganate and the loss It will be seen from the above table that in 24. hours the unstabilized hydrogen peroxide lost 21.1% of its active oxygen when heated at 100 C. This is in contrast with the peroxides stabilized with colloidal tin wherein the loss, after 24 hours, was about 8 that of the untreated sample. It will be noted that amounts of tin so small as 2 parts per million is suflicient to efiect an enor mous stabilizing action upon unstabilized hydrogen peroxide.

In order to determine the effect of an aqueous colloidal dispersion of tin upon so-called commercial hydrogen peroxide, a sample of commercial 30% hydrogen peroxide of relatively low purity was obtained and portions thereof treated with the aqueous dispersion of tin. To one sample there was added sufiicient of the tin sol to produce a peroxide containing 2 parts per million of tin and, in another sample, 20 parts per million of tin. The untreated commercial hydrogen peroxide and the treated peroxide were subjected to the accelerated decomposition test by heating in the water bath for 24 hours. Thereafter, the various samples were tested for their hydrogen peroxide and the amount of active oxygen loss during the heating period was determined. The

3 results of this test are set forth in Table II as follows:

Whereas in the relatively pure product'treat'ed' as set forth in Table I, substantially equivalent stability was obtained with 2 partsipertmillion of tin or with parts per million of tin, theconrmercial hydrogen peroxide which had not. been redistilled possessed better stability in the presence of 20 parts per million of tin than it did wriemreatedwitn 2"pjarts'per million of'tirl'.

' In accordance-withthe present invention,- it round that the amount of tin-required tostaliilizethe hydrogen peroxide depends upon the initialdegree' of impurity of the peroxide to bastabilized and; in general; larger amounts-of colloidal" tin are required, the higher the initial impurity: In' general; the" amount of colloidal tin, b'asedon the aqueous hydrogen peroxide, will rrot exce'e'd about50' to 100 parts per million of tin and; inmany instances, addition of 20 to-SO parts per million will be-foundsufficient destabilize the usual commercial" grade of" hydrogen per-=- oxide: Irrgeneral, a somewhat-greater stabilizing 3 actionispbtaihed, tliehi'ghe'r the concentration of coll-oid'altim Howeven'at every high concentration as, for instance, 100 parts per million of tin, a slight turbidityi'screated in the peroxide solution' The colloidaltin may be. used advantageously on all types of commercial hydrogen peroxidevwithin the pH range of from pH 2.5 to 7.

Although it is best to prepare the tin $01 in distilled water and add predetermined amounts of the sol to the peroxide to be stabilized, a colloidal dispersion iOf tin may be prepared directly in the peroxide solution by striking an are. between pure tin electrodes immersed in the hydrogen peroxideto be-stabilized. As an example, ti-nelectrodes were. immersed .in a solution oLunstabilized I hydrogen peroxide andarcingobtained from the.

usual-lllo volt source. Arcing wascontinuediuntil thehyd'rogen preroxidebecame. turbidwhereupon arcing was stopped and'coarse particles. of metal lictinpermitted'to' settle out by standing for M 2.4;.hours. The. resulting hydrogen p eroxi'dezpossessed'a .very faint brown.turbidity,. and stability testsweremade. on the so treated hydrogen per oxide and'upon anuntreatedsample oflthe origi' nal..unsta.hilized 30%. hydrogen peroxide. The results. of-these tests are set forth in Table-III.

In. general; greatercontrol is possible by first preparing an aqueous: dispersion of colloidal tin and sucltsolution. as'thestabilizing agent fonthe' peroxide' rather: than producing the; 001

d loidal tin directly by arcing within the peroxide solution. Where the latter method is used, the resulting peroxide is generally turbid and generally contains more tin than that required to produceva cgivenrstabilitye- Although: dependable results of. stability are obtainable from accelerated decomposition tests of. hydrogen peroxide, the various samples tested as above were also permitted to stand in glass overa period ofl-m days and tested periodically for'-activ'e= oxygen content. The samples were stored. at-.- 45 C,,. as temperature considerably higher than that .to' which commercial hydrogen peroxide subjected in normal transportation and storagenonditiona The samplesoutlined in Table I, when permitted'tostand'for 112 days at 45 0., gave the following results when titrated to determine the loss-"inactive oxygen:

TABLE IV h Percent Loss of Sample Active Oxygenin 112 days- Untreated 30% redistilled peroxides. .a (70 days); 30% redistllled peroxide plus 2 p. p; zn' tin 1. 9. 30% redistilied peroxide plus 20 p". p.. in. tin 058';

The sampleslisted in- Table I'I'were-permitted to stand at 45C. and were testedperiodically for 112 days with the-following" result:

TABILIEP}v V W Percent Loss of Sample Active Oxygen 1.!1112 days Untreated commercial 30% peroxidee. r 74 Oommcrc al=30% peroxideplus 2p; p. m; ti'IL; r. 5? Commercial 30% peroxide plus 20 p, p. in. tin 8 7 The stabilizingaotion of'colloidal tinis just aseffective upon concentratedperoxide solutions asu'pon dilute solutions. An aqueous 'sol'utionof peroxide containing.9.0'% hydrogen peroxide was treated with :2. p. p. m.-..tin. An aliquot portion of. the so treated'soluti'onwas heated in the-water. bath for. 24. hours in -.an.. accelerated decomposition test. while. another. aliquot was permitted tostand at 45? (3.1011. 1l2'..days.. Even so-little tin as 2 parts per milliongaveremarkable stability. to the sample:

TABLE VI.

Llercent4 IPerccnt 'ossin2 'ossll2v Sample hrs. at days at C. 45 C."

Untreated 90%hy'drngen peroxide 261- 3' 29 90% hydrogen. peroxide-plus 2p; -p m.itin 5. 6' 5:3

' of .the original peroxide.

3. An aqueous solution of commercial hydrogen References Cited in the file of this patent peroxide containing colloidally dispersed metallic UNITED STATES PATENTS tin in amounts greater than two milligrams per men Number Name Date 4. The method of stabilizing an aqueous hy- 5 1213921 Llebknect et J 1917 drogen peroxide solution which comprises dis- 1,536,213 Halvorsen May 1925 persing colloidal metallic tin therein. 1958'204 Relchert May 1934 5. The method of stabilizing an aqueous hy- FOREIGN PATENTS drogen peroxide solution which comprises adding Number Country Date colloidal metallic tin in amounts at least equal to 10 233 856 Germany June 4 1910 2 parts per million based on the aqueous pern oxide. OTHER REFERENCES EDWARD S- S Mellor, Inorganic and Theoretical Chemistry,

HANS O. KAUFFMANN. 1922, vol. I, pp. 936-937.

15 Bancroft, Applied Colloid Chemistry, 2nd

Edition, 1926. Page 214. 

1. AN AQUEOUS SOLUTION OF COMMERCIAL HYDROGEN PEROXIDE CONTAINING COOLOIDALLY DISPERSED METALLIC TIN. 